Brake-applying apparatus



Nov. 1B, 1927u 1,649,444

C. BUSHNELL BRAKE APPLYING APPARATUS i Filed Sept. 5, 1925 2 Sheets-Sheet l 1, 9,444 C. s. BUSHNELL BRAKE AP'PLYING APPARATUS Filed sept. 5,*1925 2 sheets-sheet 2 INV N TOR.

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Nov. I5, T927.

Patented Nov. 15, 1927.

UNITED STATES PATENToFFice.

CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAAL RAIL- WAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

BRAKE-APPLYING APPARATUS.

Application filed September 5, :1925. Serial No. 54,745. n

This inveiitionrelates to apparatus for automatically applying the brakes for train control purposes on trains equipped with an air bra-ke system off the usual type, commonly known Yas the l/Vestinghouse automatic air brake system, and more' particularly to improvenients in such automatic brake control apparatus vwhich will provide a mined reduction in brake pipe pressure to give a deiinitel brake application under,

normally running conditions, and which will also give vsuch definite brake application, or as much as is available,even thoughthe automatic application should occur immediately after a release of the brakes and before the system is re-cliarged. Y

For various reasons, familiar to `those skilled in air brake yart, it has been proposed to construct the air brake control apparatus used in train control systemsso that thisv apparatus will produce a predetermined or limited reduction in brake pipe pressure, ordinarily a reduction corresponding'to va 'full service application. The various reduction limiting devices proposed have allthe pressure in the auxiliary reservoirs and available Jiior braking, lon account of the fact that the auxiliary reservoirs are fed from the brake pipe through the restricted feed grooves. While this excess pressure in the brake pipe, above that in the auxiliary reservoirs, may exist only for a relatively short time, while the re-charging operation is occurring, it is possible in a train control system y for the automatic brake applying operation to occur during this time; and `from the standpoint safety, it is considered important that t ie brakes be applied asetfectively predeterand represents the and in any reservoir vdirectlyv connected thereto, is for a time higher than Y as possible, without any interference by the reduction limiting device.

In accordance with the present invention,

it is proposed to provide a reduction limiting device, in connection'with a suitable automatic brake applying means, which has" its operation based upon 'the'pressiire existing inthe auxiliary reservoirs, or the equivalent, and yactually available iorl braking,

rather than upon'th'e brake pipe pressure existing at the instant theautomatic braking operation occurs. More specifically, it' is proposed to provide a device comparing the existing brake pipe pressure and the pressure in the auxiliary reservoirs, or' equivalent, and combine this device with an automatic brake applying apparatus, having a predetermined or limiting reduction feature, in such away that the operation of the limiting reduction means will not begin in eii'ect until the brake pipe pressure is the sameor lower than the pressure in the auxiliary reservoirs. y l

lVliile the characteristic features of the invention, broadly considered, Amay be obtained in various ways and With various types of devices, one speciiic object of the invention is to improve the type'ofautomatic brake applying apparatus and reduction limiting means which comprises an equalizing reservoir, or equivalent, cliarcred at the existing brake' pipe pressure, an a reduction reservoir, so that the reduction reservoir. is connected to atmosphere until the brake pipepressure is the same or less than that in the auxiliary reservoirs of thetrain-` Other objects, purposes and characteristic features of the invention will be in part obvious and in part pointed out, as the description progresses.

1n the accompanying drawings, Fig; 1 illustrates in asimpliiied and diagrammatic ,mannen one specific embodiment oi theinvention applied to a system in which the brakes are automatically applied by actuat ing the engineers brake valve to the service position and the limited reduction obtained by connecting the' equalizing reservoir to a.

pose in the modifications of Figs. 1 and 3.

Before taking up in detail the description of the construction and operation of the specic devices illustrated, it should be understood that the particular means shown is merely typical and illustrative, and is susceptible of material modi [ication or adaptation by the use of various devices well known in the art-and the application of expedients that will be obvious to those skilled in the art.

The means for automatically applying the brakes and constituting the present invention is not limited to any particular type of train control system, and may be employed to produce an automatic ybrake application, whenever desired, to'carry out a train control function, whether an automatic stop, a permissive stop, or a speed control system. Ordinarily, in the usual type of train control system, tlie brakes are applied by opening a normally closed valve. For the purpose of explaining the invention it is assumed that an electro-pneumatic valve will be used for this purpose, and that its normally closed energizing circuit will include .a contact, diagrammatically shown and designated 1, which is opened at the time an automatic brake application is desired by the operation of the train control equipment.

The particular electro-pneumatic valve E. P. V. shown is one specially designed to facilitate adjustment and maintenance. This valve E. P. V. is of the solenoid type, and comprises a body portion 2 of magnetic material, a stationary core 3, riveted or otherwise secured to said body portion, and a movable core 4. The upper end of the stationary core 3 is shaped to receive the conical end of the movable core d, a residual ring 5 of suitable non-magnetic material being provided to pre-vent direct contact between the cores. The movable core 3 is guided by a sleeve 6 of non-magnetic material, preferably brass, which is held in place by a detachable cap 7. A coil 8 of usual construction surrounds the sleeve 6. Secured to the bottom of the body member by an air-tight joint is a detachable valve housing 10, having an axial cylindrical opening therein aligned with the cores 3 and 4l. rlightly fitted in this opening of the valve housing 10 is a double valve seat 11, locked in place by a transverse pin or screw l2.

Adapted to seat on the lower valve seat' is a valve 15, which is guided in the cylindrical opening in the valve housing 10, and which is urged upward by a compression spring 16 held in place by a threaded cap 17. Adapted to`seat on the upper valve seat is another valve 18, which has a stem 19 integral therewith to engage the lower valve 15. Extending loosely through the fixed core 3 is an operating pin or rod 22, engaging the upper valve 18 at itsl upper end. Suitably secured to the upper end of this operating rod 22, or integral therewith, is a member 22 threaded into the movable core et, said member 22d being conveniently fastened in its adjusted position by a Cotter pin 23 in a transverse slot in the upper end of said movable core. The member 22a isk urged upward by a spring 211, interposed between a boss on the movable cap 7 and a flanged nut 25 on said member, said nut being conveniently fastened in its adjusted position by a transverse Cotter pin.

rllhis construction facilitates adjusting the electro-pneumatic valve E. P. V. to have the desired operating characteristics. The downward movement of the operating rod 22 being limited bythe seating of the upper valve 18, the working air gap between the cores 3 and a may be adjusted by turning the member 22a in the movable core 3. The upward biasing on lthe movable core 3, provided by the springs 16 and 2a may be adjusted. The area of the upper valve 18, exposed to pressure with this valve seated, is preferably made slightly smallerV than the area of the lower valve 15, exposed to atmospheric pressure when seated, so as to obtain the desired difference inthe pick-up and drop-away currents. In order that the valves 15 and 18 may not be sluggish, due to trapped pressure, their guiding portions are preferably formed with longitudinal grooves, as indicated by dotted lines, and passages are also preferably provided to establish a connection between the opposite ends of these valves. The space between the upper and lower valve seats of the double valve seat 11 is connected by a passage and pipe to the brake valve actuator, hereinafter described; the space above the upper valve seat is connected to a port At. leading to atmosphere; and the space below the lower lUU valve seat is connected `by a passage and pipe n to a source of pressure, such as a main reservoir. ItV will be evident that, when this valve E. P. V. is energized, pressure is supplied to the brake valve actuator', and when deenergized, this pressure is cut off, and the brake valve actuator vented to atmosphere.

Brake valve actuationln the embodiment of the invention shown in Fig'. 1, the brakes are automatically applied by shifting the usual engineers brake valve, regularly used by the engineer in making manual brake applications, to the service position,

prevent the 'automatic application.v The.vv

specific construction of thev brake valve kactuator is not material to the present invention, and since the construction of a bralve valve actuator suitable for this purpose is disclosed in detail inii'ny prior "application, Ser. No. 16.973, filed Marc-i120, i925, Ihave shown herein in simpliied and diagrammatic manner; merely the important parts of this device, and will describe its construction and operation only so aras requiredto make its functionsand characteristics understood. f 1 y `.The engineers brake valve, including the usual equalizing. discharge pistonvalve 35,v is shown diagrammaticaliy, partly vin section andrpartly inoutline', and designated as a Whole BV. The rotary valve (not shown) is lined to the Voperating stem oi shaft 36, which entends upwardly above the casing of the engineers valve proper into a casingof the brake actuator mechanism.y the partsl and casing being shown cut aivay and separated to simplify the illustration. The passage and preliminary service exhaust port, connected to the upper side ot the equalizing discharge piston valve 35, used in the ordinary construction ot engineers brakek valves is omitted or plugged up, so that the equalizing reservoir is not exhausted to atmosphere in the usual Way, When the Vengineers valve is in the service position. To the upper end of the. operating stem 36 tir-ed a special service exhaust valve 37, shown in simplified forni, izing reservoir to a reduction reservoir, when the rotary valve and its stem 3SA are in Vthe service position, and which also connects the reductionreservoir to atmosphere, vhen the rotary valve is in the running position or also thelapfpositiom as fully' eX- plained in my prior application above mentioned. By reason of this. construction, Vivhen the engineers valve is moved to the servico position, either automatically or manually, equalizing reservoir pressure, insteadrot being exhausted directlyy to atmosphere, is 'exhausted into a reduction reservoir. it will be evident that, by properly propoi'tioning the volumes of the equalizing reservoir and the reduction reservoir, the lovvest pressure to which the equalizing reservoir may drop, that of equalization, can be made any desired ratio or proportion orn the initial pressure. In this Way, the maximum reduction in equalizing reservoir pressure, and likewise in bra-ke pipe pressure, may be limited to some selected predetermined value When an automatic brake application occurs.

Referring now to the means for shifting the valve stem 36 to the service position, and disconnecting the handle, the handle 38- is integral with a plate 39 loosely mounted on.

which connects the equalrsupplied to the large piston 53,

quently,

the stem 36. Keyed, or otherwise rigidly connected, to the stem 36, is an operating member 40, conveniently called a spider, `which carries a pivoted latch eti, one end of Which is pressed outward by a. spring eil-2, interposed between said latch and a projecting lug on the spider 40, in position to engage the end oit a curved stop 43 integral with the rhandle plate 39. An upwardly projecting lug a4, integral *ith thehandle plate 39, engages 'a projecting arm l5 on the spider 40, so as'to connect the handle plate to the stem 36 for'counter-clockwise movement, that is, in, a direction toward the ser.-

vice or emergency positions.y ln other Words, the handle is always operativelyconnected to the valve stem 36 to apply the brakes.

/Vith the latch l-l in its normal engaging y position as shown,

the handle is also con-l nected to the valve rstem 36 for movement in a clockwise direction, that is, 'in directionv toward the running or release positions.

Loosely mounted on the stein 36 above spider 4()V is a Apinion 50, which is connected by a rack to small piston 52 and a large piston 53 in corresponding operating cylinders. Fitted tothe pinion 50 'is a downwardly projecting pin 55 arranged so that, when said pinion is rotated counter-cloch- Wise, this pin engages a projection el on the latch et() and rocks -this latch-,in opposition to the spring and disengages it :trom the y lug 43 on the Vlatch plate 39. Another down-V Wardl aro'ectinoL 'in-5G secured to the pinion 50, is arranged to engage the projecting lug l5 on ,spider 40, When the pinion is turned.

The small piston 52- is exposed at all times to main `reservoir pressure. This same main reservoir pressure is normally the so long asr the valve E. l?. V.V is energized. i Consethe parts are normally in the posi-` E. PAV. is detion shown. `Whenithe valve energized, and the pressure is exhausted j 'from the face of the pressure on `the small piston' 52 large piston 53, the moves the rack 5l tothe left and turns the pinion 50, Y

first disengaging vthe latch -l-l, and then through engagement of the pin with the projecting arm eil, shitts the spider 40 and the valve stem 36 tothe service posi ion. In this position, the equalizing reservoir connected to the reduction reservoir by the valve 37, as previously enplained and the brakes are automatically applied in the usual Way through the equalizing valve 34 as the pressure in the equalizing reservoir drops. In this connection, itl should be understood that the, ports or passages are so proportioned that the pressure in the equalizing reservoir kdrops slowly at the desired rate, in accordance with regular-air brake ractice.

Then the electro-pneumatic valve E. P. V.

Of un) l is again energized, pressure is supplied to the large piston 53, and the rack 5l and pinion 50 are restored to the normal position. The valve stem 36 and the spider 40, howcver, remain in the service position due to the friction, there being no positive driving connection, in this particular construction, between the pinion50 and the spider l0, tor movement of the stein 36 toward the release position. The engineer may move his handle 38 to the service position and allow the sprino' L2 to torce the latch 4l into locking engagement, whereupon the engineer may restore the stem 36 and the rotary valve to the release or running position and release the automatic brake application. Then the stem 36 is returned to the lap position, the equalizing reservoir is cut oil from the re duction reservoir, and in the same position, or in the running position, as desired, the reduction reservoir is eight-usted to atmosphere. Various specilic features and advantages of the brake valve actuator described are pointed out in t'ull in my prior application above mentioned; but, tor an understamling of the present invention, it is sufiicicnt to note how the automatic application, with a limited reduction, is produced as already explained.

ReZease Valen-One of the important elements ot the combination constituting` the present invention is a device, preferably pneumatically operated, and convenientlyv termed a release valve, which serves, generally speaking, to connect the reduction reservoir to atmosphere whenever and so long as the brake pipe pressure is higher than that existing in the auxiliary reservoirs on the train and available for braking. In the modification shown in vFig. l, the pressure equivalent to that existing in 'the auxiliary reservoirs on the train is taken to be that in 'the pressure chamber of the ydistributing valve forming part of the well lrnown ET. equipment for locomotives, this pressure chamber being in eiliect the auxiliary reservoir tor the locomotive and tender equip ment, as will be readily understood by those skilled in the air brake art. Consequently, the release valve ink question serves to connect the reduction reservoir to atmosphere when the bralie pipe pressure exceeds that in the pressure Achamber oi' distributingl valve.

The release valve, designated as a whole #D DV, is shown in longitudinal section in Fig. l and in transverse section in Fig. This valve DV comprises a body portion 60, provided with supiliorting brackets 60, which in general is a box-like torni, with a detachable cover 6l, and which has circular openings in its upper and lower ends, surrounded by iianges. Plungers 62 and 63 connected by a curved web 64, are guided in the openings in the end oit' said body portion 60,' and to these plungers 62 and 63 are secured, by clamp washers and nuts 68 and 69, llexible dia` phragms 66 and 67. The edges of these diaphragms are clamped between the flanges on the body portion 6() and covers 7 0 and 7l, these covers together with the diaphragms forming upper and lower closed chambers or compartments 72 and 73. The upper chamber 72 is connected by a pipe 74 to the pressure chamber 7 5 of the distributing valve, this valve being shown in ,the outline, with no attempt to illustrate its operating parts. `The lower chamber 73-is connected to the equalizing reservoir, or to the brake pipe, preferably the latter.

Fastened to the main casing 60 by tap bolts 78 and 79,. is a valve housing 77. In this valve housing 77 is a valve seat 80, preferably locked in position by a transverse screw or pin 8l, and a valve 82, urged upwardly from its seat by a spring 83. Into the top ot the valve 82 is threaded a plunger 85, locked in its adjusted position bylock nuts 86. rIhe head of this plunger is engaged by the upper plunger 62. The valve seat is connected by Va passage 87 in the valve housing 77, a passage 88 in the main casing 60 (Fig 2), and apipe 89 to the reduction reservoir. valve seat is connected by a port 90 to the inside ot the main casing 60 and thence to atmosphere by leakage or through a suitable port rt.

Under normal running conditions, the pressures in the pressure chamber of the distributing valve and in the brake pipe are equal; and consequently the pressures on the diaphragms 66 and 67 are equal. In addition to the upward and downward pressures, depending on the exposed areas of the diaphragms 66 and 67, there` is the weight ot' the plungers 62 and 63, and their connecting web 64, and also the pressure of the spring 83, to be considered. The spring 83 is preferably light, exerting merely sutcientforce to open the valve. Taking these fac tors into consideration, the exposed areas of the diaphragme 66 and 67 is preferably proportioned so that, with equal pressures in the chamber 72 and 73, the valve 82 is closed. The plungers 62 and 63 are ot diierent diameters merely to facilitate assembly.

Operation-From the previous explanation, it will be readily understood how the brakes are Vautomatically applied and released under normal conditions. Vhen a manual brake application is made, there is the same limited reduction in equalizing reservoir, corresponding to the relative volumes or' the equalizing reservoir and reduction reservoir, so long as the engineer leaves his brake valve in the service position. The engineer can readily obtain a greater reduction, however, by restoring his valve to the lap position to exhaust the reduction reser- The spacey above they voir, and then returning his valve to the service'position.

Coming now to the special, and rather unusual` conditions which the present invention is. designed to satisfy.. imagine that the engineer makes a manual brake application, Jror example, a application, and that at this time, with the brakes released and before the auxiliary reservoirs on the cars of the trainhave been fully re-charged, thebrake valve actuator is automatically operated. Under these conditions, the pressure in the brake pipe and in the equaliaing reservoir is abnormally high, being directly connecte-cl to the; main reservoir, which is probably at a higher pressure than normal, Adue to the operation ot the excess pressure governor head. Not only is the pressure in the equalizing reservoir, likely robe above the normal ruiming pressure, but also the pressure in the equalizing reservoirs of the cars `is much lower than the normal pressure. The time taken to re-charge the auxiliary reservoirs on the car to their normal condition varies with a number o Jfactors; but there frequently a time-interval or as long as ten sefondspduring whichtheautomatic brake application may occur beforevthe bra-king system is fully re-charged.

Visualizing these` conditions, it will be readily appreciated that the limited reduction in the equalizing reservoir pressure, when charged at this temporary excess pressure, may. well fail to reduce the brake pipe pressure below that in the auxiliaryrreservoirs on the cars ot the train and produce any application of the brakes at all. Even it' there is some reduction in brake pipe pressure below that in the auxiliary reservoirs, and some application ofthe brakes occurs, nevertheless such brake application is less than that available, sinceV the reduction in brake pipe pressure is cut ott on account ot the limited reduction Jfeature with reference to the excess pressure in the equalizing reservoir, rather than with respect to the available braking pressure in the `auxiliary reservoirs. lVith this explanation, it can nowbe pointed out how the release valve DV coopcrates with the other devices of the system ot my invention to produce a brake application under these peculiar conditions, and ,making in fact the sam-e limited -reduction in the brake pipe pressure as if it were the same as the pressure in the auxiliary reservoirs. Under the special conditions in question` with the air brake system only'partially re-charged, and with excess pressure in the brake pipe and equalizing reservoir, the pressure in the pressure chamber 75 of the distributing valve is lower than that in the brake pipe. and consequently the valve 82 is open. .Vhen the brake valve. actuator is automatically operated, and the equalizing full service` then releases this A reservoir lconnected to the reduction reservoir, the pressure. in the equalizing reservoir is vented into the reduction reservoir and thence to atmosphere through the open valve 82; and this venting continues until the excess pressure in the equalizing reservoir is relieved, and this pressure is equal to, or slightly less than, the pressure inthe pressure chamber 75, whereupon the valve 82 closes. Vllhen the valve 82 closes, the reduction reservoir then becomes eective amount of reduccion that will occur equalizing reservoir. limited reduction feature ,does not start to take effect, so to spealgrintil thepressure in the equalizing reservoir and brake pipe has dropped to correspond with what is available for braking. Putting it another way, the pressure limiting device koperates on the basis otV pressure' in the auxiliary reservoirs onthe train, and actually available forl braking, "ather thanupon the pressure in the equalizing reservoir existing at the; instant the automatic brake application takes place.

Itis preferred to connect the lower chamber 7.8 or the release'valve DV to the brake pipe rather than tothe equalivzing reservoir, because leakage would then be less objectionable. In this pret-erred arrangement, the brake pipe pressure may drop slower than the pressure in the equalizing reservoir, due to the greater volume'of; the brake pipe, and the valve 82 may not close, with they chamber 73 connected to the brake pipe, unt-il after the pressure in the equalizing reservoir has fallen lower than vthat in the ber 7 5 andv in the auxiliary reservoirs on the car. thereby resulting in aheavier automatic reduction. This is on the side otv safety, and with` a long train in particular, is considered to be preferable. It should be understood, however, that the lower chamber 73 of the release valve DV inthe corrosion orthe like, likely to tail to operate properly 4when required, as sometimes' happens with valves which remain stationary 'tor long periods. n

Modification 0f Fig. 3.-In'Fig. 3, I have shown the release valve DV applied to a brake applying device separate 'from the engineers brake valve. This brake applying device, which is. shown in the simplified toria andl iscommonly termed anv applica-v to determine the pressure cham'- may be connected. to the equalizing reservoir,` without materi- In other. words, the. l

Cil

tion valve, operates to makeV a limited reduction in brakes-pipe pressure at the service rate, and also to prevent charging of the brake pipe in some suitable Way, as by cutting oii" main reservoir pressure from the engineers bra-ke valve, so that the automatic brake application occurs even if the engineers bral-:el valve is in the running condition, or the engineer tries to prevent such brake application by putting his brake valve in the release position.

In the application valve V sl'loivn, which is a simplitied form and is merely typical of devices of this character, a piston With a relatively small vent hole 106 therein, fits in a cylinder portion, and is urged to the inactive position shown by a spring 107. This cylinder portion opens into a valve chamber supplied with main reservoir pressure; and this pressure actsl on the leit hand side of the piston 105. The space in the cylinder portion on the right hand side ot the piston 105 is connected by a. pipe 108 to an electropneumatic valve EV, which closes off this pipe When energized, and exhausts it to atmosphere When de-energized. This valve EV is preferably a modiiied form of the valve EPV shown in Fig. 1, embodying the same features of construction, but using only one valve. The piston 105 is connected by a stern 109 to a slide valve 110 in the usual Way.

The parts are shown in their normal inactive position. With the valve EV energized, the pressure is equalized through the vent hole 106 on both sides vofthe piston 105, and the spring' 107 moves the slide valve 110 to the position shown. In this position, main reservoir pressure is supplied through passage 111 to the brake pipe, so that the engineer may release and re-charge in the usual Way. The brake pipe B. P. is connected by a passage 112 to the space under'- neath the equalizing dif-'charge piston 113, ot the same construction used in the bottom ot the usual engineers brake valve. The brake pipe is also connected through the passage 112, cavity 114 and passage 115 to the upper side of said discharge piston 113 and to an equalizing reservoir 116. A reduction reservoir 117 is connected by pipe 118, passage 119 and cavity 120 in the slide valve 110 to an exhaust port 121. This reduction reservoir is connected to the release valve DV by a pipe 122, in the same way as in Fig. 1.

Vhen the valve EV is cle-energized, the pressure on the right hand side of the piston 105 is exhausted at a greater rate than it can be'supplied through the vent hole 106, and said piston is forced to the right against the opposition of the spring 107, the slide valve shitting to the brake applying position. In this brake applying position, the valve laps passage 111, cutting ott main reservoir from the engineers brake valve, so that the automatic brake application is not prevented. Also, the cavity 120 in the slide valve 110 connects the passages 115 and 119, putting the equalizing reservoir 116 and the reduction reservoir 117 into direct communication. The pressure in the equalizing reservoir 116,

therefore, reduces, preferably gradually at t the service rate, until the pressure in these tivo reservoirs equalizes. By proportioning the volumes of the reservoirs 11,6 and 117, this equalization pressure may be made anything desired, to lgive a brake application ot the desired intensity. As the pressure in the equalizing reservoir 116 drops, the discharge piston 113 vents the brake pipe pressure at the same rate and to the saine amount, the discharge of this valve being to atmosphere through passage 123, cavity 124 and exhaust port 121. When the valve EV is again energized, in the simplified construction of application valve shown, the piston 105 returns tothe inactive position, exhausting'the reduction reservoir 117 to atmosphere, and connecting the equalizing reservoir 116 to the brale pipe. It is desirable, however, that the engineer should perform some positive act `to release the brakes after an automatic application; and it should be understood that the application valve AV is preferably constructed in a suitable manner, not shown in the simplified form, such that the valve will not return to the normal position, alter an automatic operation, unless the engineer moves his brake valve to the lap position, for example, or otherwise does sonic positive act.

It Will be observed that the automatic brake application, and the limited reduction feature, in this modified form of Fig. 8, is accomplished by devices performing the same or equivalent functions 'as those shown in Fig. 1 and hereinbetore explained. `Consequently, it would seem to be unnecessary to explain the `complete operation 'ot this modified form, and point out how the release valve DV serves toassure a brake application of a delinite intensity, even though the automatic operation occurs during the critical time that the braking system is being recharged aiter a previous manual application. It will be readily appreciated that, until the brake pipe pressure drops to the point Where itis the same, or slightly higher than, the pressure in the pressure ch amber of the distributing valve, the reduction reservoir 117 is connected to atmosphere. and the limited reduction does not begin, so to speak.

Where a separate equalizing reservoir and equalizing discharge piston andvalve are used. as in Fig. 3, it is possible to use some expedient,` such as a restricted port, bypassed by a check valve, in the connection between the equalizing reservoir and the brake pipe, such that the pressure in the equalizing reservoir vvill build up trom the brake pipe at a relatively slo'vv rate, compared with the rate at Which the auxiliary reservoirs on the `application stop,

train re-charge, and yet exhaust into the reduction reservoir at a higher rate, corresponding to the service rate of 'venting the brake pipe. Such an arrangement would serve to assure an automatic brake application following a manual application and occurring during the recharging period. For example, a' r scricted orifice and check valve, such as diagrammaticallyshown inFiga and hereinafter explained, may be placed in the passage 115 between the equalizing reservoir 11G and the passage leading to theA upper side of they equalizing piston 113.V In such a modified forni, which is obvious, and has not been separately shown, the release valve DV may be omitted, and reliance placed upon the restricted orifice to prevent building up pressure 1n the equalizing reseiqu voir at a rate faster than the pressure builds rup in the auxiliary reservoirs on the train, so that any automatic application gives a limited reduction in brake pipe pressure based upon the pressure in the auxiliary rc ervoirs and available for braking, rather than the excess pressure that may exist in the brake pipe.v It is important, it is believed, that there should be no restriction in the passagesconnecting the opposite sides of the discharge piston 113. Otherwise in the tivoan improper brake appli cation may occur upon the release of the first application, perhaps emergency in character, because-the pressure in the equalizingreservoir 116 and in the chamber above the equalizing piston 113 would be lover than brake pipe pressure. 1

For the same reason, a restricted orifice in the pipe connecting the equalizing reservoir 2O to the engineers brake valve of Fig. 1, While it would serve a similar function to the release valve DV, would be objectionable under ordinary conditions, proper brake application might occur when the engineer made a graduated release. To explain, when the engineer makes a graduated release, raising the brake pipe pressure slightly, and brings his brake valve to the lap position, a small. volume in the chamber above the equalizing discharge piston' 35 (Fig. 1) is quickly equalized with thelovver pressure in the equalizing reservoir 20, causing the equalizing discharge piston valve to open. l

lVhile the release valve DV, or a device performing equivalent functions, is preferred, since it takes care Vof allcommon operating conditions, l desire to have it understood, however, that'my invention embraces a restricted feed port in the pipe bctvfccn the engineers brake valve and the equaliaing reservoir 2O in Fig. 1, anda reF stricted feed port, preferably by-passed by acheck valve in the passage 115 connected to the equalizing reservoir in Fig. 3, although such specific adaptation or modification, as

Vof tl? because an 1m-v `specific embodiments of the invention,

a substitutefor the release valve DV, hasnot been specifically shown.

rlifcclz'fcazfou of F iig. .(uln Figs. 1 and 3, l have shown chamber of the release valve DV, above the upper diaphragme 6G, connected to the pressure chamber of the distrib uting valve of the vvell lnovfn E. T. equipment, it being ccnten'iplated that tbe pressure in said pressure `chamber vvill correspond vto that existing in the auxiliary reservoirs on the cars of the train. On account of the more frequent use of i ve triple valve iii-the d .itribi-t ing valve, the re-fultant vear, someliines app? s, ,at the p s Y in the pressure chamberA builds up at in the ordinary' auxiliary leakage; by the triple valve piston, as Well as supplv through the feedgroove. On account s, and also to avoid establishing av connection through the pressure chamber of the distributing valve, contemplate that, if desired, a special reservoir may be provided, as shown in Fig. et, to have therein a pressure comparing Witlrtliat vin the auxiliary reservoirs of the train. Referring to Fig. 1, the reservoir 130 isconuected by a pipe 1,31 to the upper chamber 72 of the release valve DV. This reservoir is connected by an' adjustable.restricted orilice 132ftothe brake pipe B. P., and this restricted orifice 132 is by-passed b va suitable checlr valve 133 shown as a simplified form ofa ball check valve. The check valve 1233 permits the pressure in the reservoir 13() to drop at the same rate as the brake pipe pressure, so that Whilel the brakes are being applied, the pressure in .this reservoir 130 corresponds closely to the pressure in the auxiliary reservoirs on the train. Upon a release of the brakes, and during the re-charging, the supply from the brake pipe to the reservoir 18() is through trie restricted orifice 132, so. that the pressure in said reservoir builds up slovvly at a rate corresponding to the rate at which the auxiliary reservoir pre builds up through the said groove in the triple valve. 1u this modified construction of Fig. a, it should be understood that the diaphragme, 66 and 67 of the release valve DV should be proportioned such that the valve is seatc'd,"as soon as theV pressure in the reservoir 130 is nearly as high as the brake pipe presure, otherwise duo to leakage and other unavoidable causes occurring in practice, the valve 82 may fail to seat.

Vhile I have shovvn and described' various it shouldv be understood that various modifb cations and adaptationsl of the particular construction illustrated maybe made Without departing from the scope. of the invention. Broadly considered, a characteristic feature of the invention resides in the provision of means which assures the-limited reduction in brake pipe pressure-occurring any objections of lill() upon an automatic brake application, being based upon the pressure existing in the auxiliary reservoirs ot the train and available for braking, rather than upon the existing brake pipe pressure, which may be temporarily high. This principle may be carried out in various ways, as already indicated. It should be understood, therefore, that the invention embraces a variety of specific constructions and combinations, as set forth in the appended claims.

1What I claim is 1. Automatic brake applying apparatus for braking systems of the type in which the brake pipe is norn'ially charged and in which a predetermined reduction in brake pipe pressure effects a Vfull service brake application, comprising, means automatically operated. by suitable train control apparatus tor ventinathe brake pipe. and means for discontinuing such venting when the brake pipe pressure has fallen to that point where a full service brake application results even though the automatic brake application is initiated immediately after the brakes have been manually released.

2. Automatic brake applying apparatus for braking systems of the type in which the brakepipe is normally charged and in which a predetermined reduction in brake pipe pressure effects a Jfull service brake application comprising, means automatically operated by suitable train control apparatus tor venting the brake pipe, and means for discontinuing such venting when the brake pipe pressure has fallen to a pressure value a predetermined degree below that existing in the pressure chamber of the distributing,r valve (forming part of the braking system) when the brake application is initiated.

3. riutomatic brake applying` apparatus tor braking systems Ot' the type in which the brake pipe is normally charged and in which a predetermined reduction in brake pipe pressure effects a full service brake application comprising, means automatically operated by suitable train control apparatus for Venting the brake pipe, and means for discontinuing venting of the brake pipe when the brake pipe pressure has tallen to that Value at which auxiliary reservoir pressure and brake cylinder pressure equalize in spite o't the fact that the brake pipe pressure may have been higher than auxiliary reserif'oir pressure at the time the brake application was initiated.

4. Automatic brake applying apparatus for braking systems of the type in which the brake pipe, the equalizing reservoir and the auxiliary reservoirs are normally charged, and in which venting of the brake pipe causes fluid pressure to How from the auxiliaryreservoir into the brake cylinder until the auxiliary reservoir pressure has fallen to that existing in the brake pipe, unless the brake pipe pressure has fallen below equali- Zation pressure of the auxiliary reservoir and the brake cylinder comprising, brake applying mechanism operated automatically by suitable train control apparatus and which if operated vents the brake pipe, and means for discontinuing such venting eliective when the brake pipe pressure has fallen to the pressure of equalization between the auxiliary reservoir and the brake cylinder pressures, said last mentioned means functioning as stated eren though the brake pipe application was initiated when the brake pipe pressure was higher than the auxiliary reservoir pressure.

Automatic. brake applying apparatus tor braking systems of the type in which the brake pipe, the equalizing reservoir and the auxiliary reservoirs are normally charged, and in which the venting of the brake pipe causes fluid pressure to flow from the auxiliary reservoir into the brake cylinder until the auxiliary reservoir pressure has fallen to that existing in the brake pipe unless brakc pipe pressure has fallen below equalization pressure of the auxiliary reser-v voir and the brake cylinder pressures comprising. brake applying mechanism operated automatically by suitable train control apparatus which if operated Vents the brake pipe, and means tor discontinuingV such venting when the pressure in the brake pipe has fallen a predetermined amount below that existing in the auxiliary reservoir at the time the automatic brake application was initiated even through the automatic brake application occurred at a time when brake pipe pressure was higher than auxiliary reservoir pressure. V

6. Automatic brake applying apparatus for braking systems ofthe type in which the brake pipe, the equalizing reservoir and the auxiliary reservoirs are normally charged, .and in which renting oit the brake pipe causes fluid pressure to flow Jfrom t-he auxiliary reservoir into the brake cylinder until the auxiliary reservoir pressure has fallen to that existing in the brake pipe unless the brake pipe pressure has fallen below equalization pressure ot the auxiliary reservoir and the brake cylinder pressures cornprising, brake applying mechanism operated automatically by suitable train control apparatus and which if operated vents the brake pipe, means for discontinuing such venting, including a reduction reservoir into which such equalizing reservoir is vented when an automatic brake application is initiated, and means for Venting said reduction reservoir to atmosphere so long as brake pipe pressure is higher than auxiliary reservoir pressure.

7. Automatic brake applying apparatus Jfor braking systems of the type in which the brake pipe, the equalizing reservoir and the auxiliary reservoirs are normally *l ico ' euses @uid pressure t iary reservoir into the brake .cylinder until .apxiliary reservoirs are and in which venting of tliebralre pipe causes iiuid pressure to vflow from the auxiliary reservoir intoftlie bralre cylinder until the auxiliary reservoir pressure v`has fallen to that existing in the brake pipe unless the brakepipe pressure has fallen below equalization pressure othe auxiliary reservoir and the brake cylinder pressures comprising, brake applying mechanism separate from .that used Ain ,etl'ecting a manual application of the bralres includinga separate` equalizing mechanism if operated connects the sepay rateequalizing reservoir to the reduc-tion reservoir and vents thebra-le pipe/to the equa'lized pressure in these reservoirs, lsaid Aseparate equalizing pressure being normally connected to the brake pipe through a re- Y a' check valve, said cheer valve permitting the exhaust ot pressure from vthe separate'equalizing reseryoironly. y

h8. Automatic 'brake applying apparatus .far blekinssystems .0f the tyre in which the lbralfge pi 4e the equalizing reservoir and the normally' charged,

.and in which' ventina flow from the auxilthe'auxi ary reservoir pressure has fallen to that e isting the brake pipe unless'the .brake @represente has yfallen below equalization pressure o f the auxiliary reservoir er pressures comprising, brake applying mechanism operated .autoanatically'by suitable'train control apparatus and h ifoperated Vents 'the brake pipe, ,means .for ClSOHtilu'ias ,511011 Vent-ills fncluding a .reduction neseryoir into which such equa'liaing reservoir is vented when an automatic brake application is initiated, a

Apressure Ireservoir connected to the brake eine through e restricted opening ,by-Passed by a check Value permitting said 'pressure reseryoir tochargev-only at the rate the auxiliary :reservoirs are charged lbut qto discharge very vqui'clrly When pressure changes'in the hralrefpressure reservoir issubstant-ally t-he .fior bralringsysteins ofthe type'inyvhich the p p saine -as that n `the auxiliary reservoirs', an

means for c oiinectipg'paid reduction reservoir t0 atmphere [S0 1011s 21S :brake Pipe .pressure .is bisher than 1pressure reservoir.

9. Automatic 'brake applying apparatus bralre gpipe, Ithe equalizing reservoir andthe fauxiliary yreservoirs are normally charged, ,and in which Venting o f the brake pipe lcauses fluid pressure to flow from the auxiliaiiy lreservoir into the brake cylinder until `the .auxiliary reservoir pressurehas fallen to L that .existing the brake pipe unless the brake pipe @researches tellen below equali- .zilteli .pressure 91" .and the fbr. kjeyllader .pressures @Ompllmg of the bra-ke pipel the pressure in theV l a Maladies the usual engineersbralre valve and a reduction reservoir, which bra-lie value is automatically operated to the service brake applying pesition by suitable train control' mechanism under` predetermined traic conditions in a manner so thatfethe engineer cannotprevent its operation and which if operated connects said' equaliZi-ng reservoir to said reduction reservoir, and means :tor connecting said reduction reservoir to Iatmosphere when bra-ke pipe pressure is-'higher than'auxiliary y While lthe :braking system is being Lifecharged.

l-I; Automatic brake applying 4mechanism for railway ali-r brake systems of the type fin -ivliich the brake pipe is normally chargedy n and in which Y'venting of the brake pipe etects a brake 'application comprising, .automat-ic 4means for Venting the brake pipe, reduction limit-ing -means lfor l discontinuing the Venting of the brake pipe when the br-ake l pipe has been vented to Va predetermined-extent lbelow the pressure existing VVtherein When the automatic brake application was initiated, and means for rendering .said reduction limiting means .inelfectiyei Ian automatic gbrake application is initiated While the pressure .in the brake pipe is Aabove-the pressure lin the .auxiliary reservoirs/ of the l2. Automatic ybrake applying mechanism -Jf or railway air :br ke `systems of fthe typein which the' brake pipe is normally charged .and in .which `Venting off :the .brake .pipe eleets a braglre Aapplication comprising,.automatic means yfor renting the :bralxe'pripm .reduction limiting means for discontinuing the venting ofthe ibrlalre pipe When .the )brake i e has been rented .to a predetermined kex- 'tentfbelow the .pressure existing :thereiniwhen the automatic brake application -was initi-Y l ated, and mea-ns --orrendeiving .said reduction limiting means ineffective if an .automatic brake-application isfin-itiated While the pressure in the pressure chamber of Vthe distributing valve of' said air :brake system is below the pressure inthe'brake pipe.

13. An electramagnetic valve comprising, an electro-,magnet of .the .slelltype teneis-t` of a magnetic shell stationary ioo perforated core projecting upwardly on the inside thereof, a movable core in alignment with but above said stationary core, valve means including a plungerfastened to the lower end of said shell, and a rod of nonmagnetic material passing through the perforation of said stationary core and engaging said movable core and the plunger of said valve means.

14. An electro-magnetic valve comprising an electro-magnet of the shell type consisting of a magnetic shell having a stationary perforated core projecting upwardly on the inside thereof, a movable core in alignment with but above said stationary core, valve means including a plunger fastened to the Vlower end of said shell, a rod of non-magnetic material passing through the perforation of said stationary core connecting said movable core and the plunger of said valve means, and adjustable means for changing the spaced relation between the plunger of said valve and said movable core.

15. An electro-magnetic valve comprising, an electro-magnet of the shell type consisting of a magnetic shell having a stationary perforated core projecting upwardly on the inside thereof, a movable corein alignment with but above said stationary core, valve means including a plunger fastened'to the lower end of said shell, means adjustably connected to said movable Vcore for forming an abutment, and arod of non-magnetic material extending through the perforation in said stationary core and having its upper end engaging said abutment and its lower end engaging said valve means, whereby said movable core is adjustably connected to said valve means.

16. An electro-magnetic valve comprising, an electro-magnet of the shell type consisting of a magnetic shell having a stationary perforated core projecting upwardly on the inside thereof, a movable core in alignment with and above said stationary core, valve means including a plunger fastened to the lower end of said shell, means adjustably connected to said movable core for forming an abutment, a rod of non-magnetic material extending through the perforation in said stationary core and having its upper end engaging said abutment and its lower end engaging said valve means, and spring means for lifting said valve against the downward pull of said movable core.

17. Anelectro-magnetic valve comprising, an electro-magnet of the shell type consisting of a magnetic shell having a stationary perforated core projecting upwardly on the inside thereof, a movable core in alignment with and above said stationary' core, valve means including a plunger fastened to the lower end of said shell, means adjustably connected to said movable core for forming an abutment, a rod of non-imag-V netic material extending through the perforation in said stationary core and having its upper end engaging said abutment and its lower end engaging said valve means, a spring for yieldingly supporting said movable core and meansfor adjusting the'tension of said spring.

18. An electro-pneumatic valve comprising, a cylindrical magnetic shell having a perforated stationary magneticcore extending part way therethrough, a valve chamber fastened to the bottom of said shell, valve in said valve chamber a movable perforated core above but in alignment with said stationary core, means threaded intothe perforation of said movable core for forming an adjustable abutment, and a rod of non-magnetic material passing through the perforation of said stationary core into the perforation of said movable core and engaging said abutment and the valve in said valve chamber. i Y.

19. An electro-pneumatic valvecomprising a cylindrical magnetic shell having a perforated stationary magnetic core extending part way therethrough, a valve chamber fastened to the bottom of said shell, a valve in said valve chamber, a movable perforated core above but in alignmentl with said stationary core, means threaded into the perforation of said movable core for Vforming anadjustable abutment, a vrod of nonmagnetic material passing through the perforation of said stationary core into the perforation of said movable core against the adjustable abutment in said movable core and having its lower end engaging the valve in said valve chamber, and spring means for yieldingly supporting saidmovable core,

In a railwaybraking system of thev type in which the brake pipe Vis normally charged and wherein venting of the brake pipe effects a brake application, automatic means for venting the brake pipe and effecting a brake application, reduction limiting means for stopping venting of the brake pipe due to operation of saidautomatic means effective when a predetermined reduc-` tion has been made after said reduction limiting means started functioning, andA means for determining starting of functioning of said reduction vlimiting means,

v21. In a railway braking system of the type in which the brake pipe is normally charged and wherein venting of the brake pipe effects a brake application, automatic means for venting the brake pipe and effecting al brake application, reduction limiting means for stopping venting ofthe brake pipe due to operation of said automatic means effective, when a predetermined reduction has been made after said reduction limiting means started functioning, and means for starting the functioning of said reduction limiting meansl when the brakel lpipe effects a 23. In a railway braking system of the type in which the brake pipe is normally charged and wherein venting oi the brake 'pipe eil'ects a'brake application, automatic means for venting the brake pipe and elfecting a brake application, and reduction limitpipe pressure has fallen to' a value corresponding to the pressure in auxiliary reservoirs of the train.

22. In a railway braking systemy of the type in which the brake pipe is normally charged and wherein ventingot1 the brake brake application, automatic means for'venting the brake pipe and effecting a brake application, andreduction limiting means including a chamber the pressure in which corresponds to that existing in the auxiliary reservoir of the train when a brake application is initiated by said automatic means. e

be charged through a restricted opening but may be discharged through a larger opening HARLES S. BUSHNELL.

ing means including a chamber which inay including a check valve for determining the Y the ultimate 

